Tumblr founder and CEO David Karp admits that one area the blogging network hasn’t performed well enough at thus far is content discovery – and you can expect to see a lot of development in that area at Tumblr.com this year.

Karp is at the DLD conference today as part of a bid to expand the international impact of the blogging service. As we reported earlier today, the startup now serves 120 million people and 15 billion pageviews every month.

We caught up with him a little later to find out more about what’s in store for 2012. A focus on growth outside the US and a larger staff headcount are planned but product development is also a priority, Karp says.

“It’s a terribly obtuse network… once you’re in, it’s one of the most enthralling places ever. Our average user spends upwards of thirty minutes a day on Tumblr and our really users spend hours a day… refreshing their dashboard.

“It’s just too hard to get started. Amazingly, people are still figuring it out and getting a ton of use out it but we need to make that easier this year.” One area of Tumblr content that Karp is particularly excited about and wants to help users access is the community of journalists who use the platform.

Meanwhile, it was good to hear that Karp is a fan of our Tumblr Tuesday feature which uncovers the stories behind interesting Tumblogs. That said, finding high quality examples to feature can sometimes be a challenge. Perhaps when better discovery features are introduced, our job will become a bit easier.

You can listen to the full interview below.